Poly(p-styrenesulfonylhydrazides)

ABSTRACT

A NOVEL CLASS OF POLYMERIC COMPOSITIONS HAVING REPEATING STRUCTURAL UNITS OF THE FORMULA   -(CH(-(1,4-PHENYLENE)-SO2-NH-NH2)-CH2)N-   THESE COMPOSITIONS FIND UTILITY AS POLYMERIC BLOWING AGENTS FOR USE IN FORMING FOAMED RESINOUS COMPOSITIONS.

United States Patent Oflicc 3,654,242 Patented Apr. 4, 1972 3,654,242POLY(p-STYRENESULFONYLHYDRAZIDES) John E. Herweh and Algirdas C.Poshkus, Lancaster, Pa., assignors to Armstrong Cork Company, Lancaster,Pa. No Drawing. Filed July 30, 1968, Ser. No. 748,658 Int. Cl. C08127/08, 27/06 US. Cl. 260-793 R 2 Claims ABSTRACT OF THE DISCLOSURE Anovel class of polymeric compositions having repeating structural unitsof the formula These compositions find utility as polymeric blowingagents for use in forming foamed resinous compositions.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to sulfonylhydrazide type blowing agents in general and morespecifically to poly(styrenesulfonylhydrazides) DESCRIPTION OF THE PRIORART An important class of chemical blowing agents useful in formingfoamed resinous products are those based on the sulfonylhydrazidemoiety. Typical organic sulfonylhydrazides are disclosed in US. patentNo. 2,830,086.

SUMMARY OF THE INVENTION DESCRIPTION OF THE PREFERRED EMBODIMENTS Asolution of the polystyrene resin in a suitable solvent such as ethylenedichloride, is added to an excess of chlorosulfonic acid to form achlorosulfonated polystyrene resinous reaction product. Thischlorosulfonated polystyrene in a suitable solvent medium, preferably apolar inert solvent such as tetrahydrofuran, is then reacted withhydrazine and the poly(styrenesulfonylhydrazide) is precipitated fromthe reaction mixture. Hydrazine hydrochloride, a by-product of thereaction, is also precipitated and removed by repeatedly washing withcold water.

It is possible to form a variety of useful polymeric blowing agentsvarying as to their molecular weight and gas producing capacity.Generally, it is preferred that the to 1.0 nuclear sulfonylhydrazidegroups per styrene unit.

The following examples illustrate specific embodiments of our invention.

Example 1 A solution of polystyrene (DOW PS-2) having a molecular weightof about 20,000 (50 grams, 0.48 mole in 180 milliliters of ethylenedichloride) was added dropwise in four hours to stirred chlorosulfonicacid (560 grams, 4.80 mole) maintained at 4 (:l) C. After standing threehours at 0 (:1) C. followed by ap proximately 16 hours at roomtemperature, the amber reaction mixture was added to ice and a white tocreamcolored solid precipitated. The filtered precipitate was trituratedand washed repeatedly with ice cold water. The aqueous filtrate andwashings were discarded; the filtercake washed with petroleum ether andfinally dried in vacuum (approximately 10 mm.) at 30i5 C. until aconstant weight was obtained. The dried crude reaction product (95.6grams) was precipitated from solution in tetrahydrofuran by its additionto petroleum ether and gave a product which analyzed as follows:

Analysis.Calculated for (C H ClO S) (percent): C, 47.41; H, 3.48; Cl,17.50; S, 15.82. Found (percent): C, 46.04; H, 3.82; Cl, 14.11; S,15.92.

A 20 gram portion of the chlorosulfonated polystyrene in 150 ml. oftetrahydrofuran was cooled to 0 to 5 C. and treaetd with 8.22 grams ofaqueous hydrazine. After standing approximately 2% hours at roomtemperature, the reaction mixture containing a finely divided solid wasfiltered. The filtered-cake was washed consecutively with freshtetrahydrofuran and ether and air-dried. The combined filtrate andwashings were discarded. The dried, finely-divided pale tan to yellowsolid was triturated and washed with cold water to remove hydrazinehydrochloride. The aqueous insoluble solid was then washed consecutivelywith methyl alcohol and ether to give 18.2 grams, after drying, ofpoly(p-styrene sulfonylhydrazide). Precipitation of the reaction productfrom solution in dimethylformamide by addition to benzene gave a productwhich analyzed as follows:

Analysis.-Calculated for (C H N O S) (percent): C, 48.46; H, 5.08; N,14.13; S, 16.18. Found (percent): C, 48.03; H, 5.18; N, 13.73; S, 15.73.

Example 2 The reaction of Example 1 was repeated using a polystyreneresin (DOW PS-683) having a molecular weight of about 200,000. 25 grams(0.24 mole) of the polystyrene resin was added to 214 grams (1.84 moles)of chlorosulfonic acid. After completing the addition which requiredapproximately 2 hours, additional chlorosulfonic acid (174.5 grams, 1.5moles) was added to the brown to amber reaction mixture possessing theconsistency of taffy to facilitate stirring. The reaction mixture wastreated as in Example 1 and the yield was 48.5 grams of a white powder.The crude reaction product was insoluble in tetrahydrofuran andanalyzed:

Analysis.Calculated for (C H- CIO S) (percent): C, 47.41; H, 3.48; Cl,17.50; S, 15.82. Found (percent): C, 44.34; H, 4.54; Cl, 11.15; S,15.36.

A 20 gram (0.1 mole) portion of the chlorosulfonated polystyrene resinwas added over a period of 30 minutes to 200 milliliters of a striredaqueous solution of hydrazine (3.76 grams, 0.1 mole) and sodiumhydroxide (4.0 grams, 0.1 mole) at 5 (:1") C. After completing theaddition,

the reaction mixture was stirred at room temperature for three hours.The alkaline reaction mixture was cooled to C. and neutralized with ninemilliliters of 3 N hydrochloric acid. The cream-colored precipitateformed in the reaction mixture was filtered and washed consecutivelywith cold water, methyl alcohol and ether. The insoluble product wasdried in vacuo to give 16.4 grams of poly- (p-styrenesulfonylhydrazideThe hydrazinolysis may also be carried out in aqueous media using sodiumhydroxide as the hydrogen chloride acceptor. Thus, powderedchlorosulfonated polystyrene from Example 1 (20 g., 0.10 mole) was addedportionwise in 25 minutes to an ice cold aqueous solution (200 ml.)containing 85% hydrazine (3.76 g., 0.1 mole) and sodium hydroxide (4 g.,0.1 mole) in a Waring Blendor. The reaction mixture, consisting of afinely divided creamcolored solid, was stirred for 70 minutes duringwhich time the reaction temperature rose to 35 C. After 1 hour at icebath temperatures, the reaction mixture was filtered. Due to the fineparticle size, filtration was extremely slow. The cream-coloredfilter-cake was slurried with cold water (100 ml.) one time andfiltered. After washing the aqueous insoluble solid consecutively withmethyl alcohol and ether, it was dried in vacuo to a constant weight(10.2 g.). An infrared absorption spectrum (KBr) of the crude productwas similar to that obtained for the product prepared using THF as areaction solvent and excess hydrazine as the acid acceptor.

The poly(p-styrenesulfonylhydrazide) of Example 1 on heating slowly inair gradually decomposed and darkened at from about 172-l90 to 300 C.Thermogravimetric analysis of a sample in air utilizing a heating rateof approximately 6" C. per minute showed a rapid decomposition with aweight loss of 26 to 28% at approximately 150 C. The weight loss closelycorresponds to that calculated in accordance with the equation:

Thermal decomposition of suspensions of thepoly(pstyrenesulfonylhydrazide) of Example 1 in Nujol at approximately150 C. proceeded smoothly to give nitrogen in 80 to 85% yield of theory.Sulfur dioxide and hydrogen sulfide were not detected as components ofthe volatile decomposition products.

The poly(p-styrenesulfonylhydrazide) of Example 2 on heating slowly inair gradually decomposed and darkened at from about 180 to 300 C.Thermogravimetric analysis of a sample in air utilizing a heating rateof approximately 6 C. per minute showed a rapid decomposition with aweight loss of 15 to 16% at approximately 160 C.

Example 3 A poly(vinyl chloride) dry blended composition was prepared bymixing a masterbatch of the following formulation in a Henschel Blendorat a temperature below about 200 F.

Ingredient: Weight in grams Poly(vinyl chloride) homopolymer havingnumber average M.W. of 26,000 and weight average of 54,000 Dioctylphthalate 70 Epoxidized soybean oil 5 Liquid Ca-Zn octoate stabilizer 450 Mesh limestone l0 TiO pigment 2 Calcium silicate 0.75 Polymericblowing agent from Example 1 2.59

Portions of the poly(vinyl chloride) dry blend thus prepared andcontaining the polymeric blowing. agent were spread to a thickness ofmils on release-type felt and were expanded in an open oven to yieldfoams of a homogenous coarse cell structure; several foams were preparedunder various conditions for expansion with varying resultant foamdensities which are recorded in Table I below.

Sample No. 5 was a poly(viny1 chloride) foam prepared from dry blendformulated in accordance with Example 3 except that 4,4 oxybis(benzenesulfonylhydrazide) was substituted for thepoly(p-styrenesulfonylhydrazide), 2.25 grams being substituted in theformulation set forth in Example 3 for the 2.59 grams of the polymericblowing agent (calculated to give an equivalent gas yield).

We claim:

1. A poly(p-styrenesulfonylhydrazide) having 0.2 to 1.0 nuclearsulfonylhydrazide groups per styrene unit.

2. The poly(p-styrenesulfonylhydrazide) in accordance with claim 1 inwhich the average molecular weight range of the polystyrene resin isWithin the range of approximately 10,000 to 500,000.

References Cited UNITED STATES PATENTS 2,520,917 9/ 1950 Dickey 260-8552,778,813 1/1957 Gaspar 260--79.3 2,830,086 4/1958 Stempel, Jr. 260-556JOSEPH L. SCHOFER, Primary Examiner C. A. HENDERSON, JR., AssistantExaminer US. Cl. X.R. 260-25 P, 899

